4.1 Capacity vs. constraints

Although the project examines both "capacity and constraints," in many cases, constraints are simply the reverse of capacity: the environmental, infrastructure, and financial limits that can influence the scale of settlements and their ability to accommodate growth. Table 1 indicates some ways of defining and determining capacity and constraints in water and wastewater services.

Table 1: Types of capacity and constraints data

Types of capacity data

Types of constraints data

  • Designed capacity of a water or wastewater plant
  • Scale and extent of major water and sewer pipes
  • Number of connections, and/or population served
  • Average and maximum flows through a plant
  • Reserve capacity
  • Plant classification
  • Aquifer capacity and water takings from aquifers
  • Surface water body capacity
  • Assimilative capacity of water bodies receiving effluent
  • Groundwater limits
  • Surface water limits
  • Type of water bodies receiving effluent
  • Assimilative limits of water bodies receiving effluent
  • Limits on subsurface sewage disposal
  • Inflow and infiltration data
  • Plant and system costs - capital, operations, lifecycle
  • Drought data; climate change data
  • Age of water and wastewater system elements
  • Evidence of failure in water and wastewater systems